Stitch-forming mechanism for circular-knitting machines



May 26, 1925 1,539,568

H.E.HOUSEMAN STITCH FORMING MECHANISM FOR CIRCULAR KNITTING MACHINES Filed June 13, 1924 3 Sheet ;Sheet l KUZWESS:

May 26, 1925. 1,539,568

H. E. HOUSEMAN STITCH FORMING MECHANISM FOR CIRCULAR KNITTING MACHINES .3 Shets-Sheet 2 Filed June 13, 1924 6 d k f d Wm? C lI Fla/0Q m 1 i lI l|l I I] D I I l l I 9" Fla WIN. imu I IIH I LA 5 MWEA/TOR lV/f/YESS: h a H ald E /%zzsmaIr M MA ' Jrra M; Y3-

May 26, 1925. 1,539,568

H. E. HOUSEMAN STITCH FORMING MECHANISM FOR CIRCULAR KNITTING MACHINES Filed June .15, 1924 3 SheetS Sheet Z- ATTORNEYS.

Patented May 26, 1925.

UNITED STATES PATENT orrice.

HAROLD E. HOUSEMAN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOB TO STANDARD- TRUM]? BROTHERS MACHINE COMPANY, OF WILMINGTON, DELAWARE, A GOR- IPORATION OF DELAWARE STITCH-FORMING MECHANISM FOR CIRCULAR-KNITTING MACHINE.

Application filed June 13, 1924. Serial No. 719,699.

To all whom it may concern:

Be it known that I, HAROLD E. HOUSEMAN,

a citizen of the United States, residing at Philadelphia, county of Philadelphia, and State of Pennsylvania, haveinvented a new and useful Improvement in Stitch- Forming Mechanism for Circular-Knitting Machines. of which the following is a full,

clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

In the knitting of fabric on circular knitting machines, it is common to arrange, alternately with the independent, vertically reciprocable needles, Web holders (usually called sinkers by practical knitters) over which the yarn is drawn in the downward stitch-forming movement of the needles. After the hook of a needle, in its downward movement, engages the yarn, it continues to move down to draw the yarn through the previously formed loop in the immediately preceding course. The needle then moves up. That part of the downward movement of the needle following the specified engagement of the hook thereof with the yarn, together with that part of its upward movement required to return the needle hook to the level at which it engaged the yarn, occupies a period of time during which the needle is traveling through an arc of rotation which may be somewhat variable but which, in a typical machine, is equal, for example, to about the distance from any given needle to a point between the fourth and fifth needle in advance thereof. This may be greater or less dependent on the gauge of the machine. Consequently at any given instant, there are about five needles whose hooks are at or below the level at which the yarn is engaged. The yarn-engaging upper surfaces of the sinkers are about on a level with the point of engagement of the needle hooks with the yarn. It is therefore apparent that, at any given instant, the yarn is engaged with about as many sinkers as there are needles at this lower level; the yarn extending under a needle hook, over a sinker. under the next needle hook, over the next sinker, and so on until a needle is reached whose hook is above the level of the top surfaces of the sinkers. Bearing in mind that, while the thread 13 occupying this zigzag position, it is being forcibly drawn through the hooks of the purposes, but whose yarn-engaging ends are also capable of'vertical movement. If I impart to each needle, after its hook engages the yarn, recessive downward and upward movements below the level of yarn-engagement of (say) half the extent of that customary in knitting on ordinary machines, and at about the same time cause the yarnengaging ends of adjacent sinkers to suecessively rise and fall (say) an equal distance, thereby performing precisely the result, as far as the knitting operation is concerned, as is performed in the case of ordinary knitting with sinkers having no other movement than the usual radial movement of projection and recession. Inasmuch as the specified speed travel down and up, after its engagement with the yarn, is but about half that in ordinary knitting with sinkers having no vertical movement, it is clear that such needle reciprocation is c ed in half the usual time and that the arc of travel of the needle during the specified down and up movement is reduced one half. Consequently, at any given instant. there are no more than two or three needles whose hooks are below the level at which the yarn is engaged thereby and the zigzag path of the thread is but about half the length of that required with sinkers having no vertical movement. Hence the strain imposed on the yarn is very materially'reduced, greatly reducing, if not almost eliminatin the the danger of breakage and also making it practicable to knit with relatively weak yam.

It is Well understood that, in the stitchforming operation, the strain on the yarn is such that yarn is not only drawn rom the source of supply, but is also robbed from stitches which have just previously been formed. It is therefore, necessary in the conventional method of knitting, to draw much longer loops than will ultimately appear in the fabric. strain is so much reduced that it is not neces sary to form loops of such eat length, thereby reducing the extent 0 the extreme downward movement of the needles relative to the adjacent sinkers, whereby the convolutions in the specified zigzag extension of the am may be reduced not only in number ut in depth.

The described successive up and down movements of the sinkers may be effected by a cam which is located at the stitch-forming point and which positively depresses the rear or outer end of a sinker arranged to tilt on a transverse axis, the depression of such rear or outer end raising the inner'or front yarn-engaging end. No means for positively returning the sinker (depressin its yarn-engaging end) need be provide as that result will be accomplished by gravity and by the pull of the yarn.

The cam above specified may be in fixed position. It is not necessary to make it adjustable in order to effect the function above described. If it is desired, in the upper part of the leg, in the welt, in the heel and toe, or in the foot, to produce longer loops, in order to widen the diameter of the web,

or to allow the insertion of an extra thread,

there may be utilized known expedients to effect any of such ends, such as shifting the needle cylinder (or cam cylinder) vertically, or moving in the sinkers radially somewhat sooner or somewhat further than in what may be termed normal knitting. These operations do not affectthe operativeness of my invention, which continues to function as described.

, However, the usual expedients for making loose stitches, while operative, are not wholly satisfactory, whether because of some degree of uncertainty or irregularity of op eration or because of purely mechanical objections. Thus, in arranging for a vertical displacement of the needle cylinder or cam cylinder, bearing in mind that provisions must also be made for both the rotation and oscillation of the needle cylinder difiicult mechanical problems arise, the solution of which involves considerable complication of mechanism having a tendency to get out of order. I have found that it is possible, without affecting the normal operation of my invention, to arrange for a variable de- By my invention, the

special cam above mentioned. Thereby the necessity of providing for a vertical movement of the cam cylinder or needle cylinder may be altogether avoided.

When, however, it is sought to adapt the invention to the production of longer loops in the sole of the foot, special problems arise, but I have succeeded in resolving these problems and in adapting the invention to this purpose also.

In the accompanying drawings, '1 have shown several different embodiments of my invention:

Fig. 1 is a detail vertical sectional View taken on a radius of the knitting machine head and showing a needle, a sinker and sinker actuating cams.

F ig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is a plan view of part of Fig. 1.

Fig. 4 is a detail vertical sectional view of mechanism for variably tilting the sink ers and also for separately tilting the sinkers in the rear bank of needles.

Fig. 5 is a plan view of the sinker actuating cams shown in Fig. 4 and of the levers carrying certain of said cams.

Fig. 6 is a side view of the devices shown in Fig. 5.

Fig. '2' is a plan view of the head of a circular knitting machine showing also the mechanism-shown in Figs. 4-6 and means for actuating said mechanism.

Fig. 8 is a side View of Fig. 7, partly in section.

Fig. 9 is an enlarged diagram showing needles, needle actuating cams and sinkers and illustrating the action on the yarn of my vertically movable sinkers in cooperation with the usual vertically movable needles, as contrasted with the action on the yarn of such needles in cooperation with sinkers having no vertical movement.

Referring first to Figs. 1, 2 and 3: the needle cylinder a carries the independently operable needles 6 and the sinker bed 0 slotted to receive the sinkers d, which are movable radially in-the usual way. In Fig. 1, this radial movement is effected by means of a cam e engaging a recess in the sinker. The sinker is of the usual construction except that its lower edge is bevelled toward its outer end so as to enable the sinker to tilt on a transverse axis.

To effect this tilting of the sinker, I provide a cam 7 adapted to engage the outer end of the sinker. The cam 7'' may be fixed or adjustable. Adjustability of this cam, or of a'ny 'substitute sinker-tilting cam, is. necessary if it is desired to rely, partly or wholly, upon tilting to loosen the stitch in any given part of the stocking; but for the purpose of attaining the mainiob'ect of my invention, the cam f ma be fixe and is so illustrated in Figs. 1 and Jun 3, being formed integral with a plate secured by screws to the upper end of a bracket g, the base of the bracket being secured to the machine frame.

The cam f is so positioned relative to the needle actuating cams that any given sinker starts to tilt just after the needle ahead of.

such sinker engages the yarn. As the needle cylinder continues to rotate, the yarn-engaging end of the sinker rises while-the needle continues its descent; while in the upward return of the needle the yarn-enga ing end of the sinker returns to its normal evel, the return of the sinker being effected as hereinbefore mentioned.

The described operation may be better understood by an examination of Fig.9, wherein it represents the set of needle-actuating cams, b the needles, d the sinkers and y the yarn. By comparing one of the needle actuating cams in Fig. 9 with the cam f in Fig. 2, it will be observed that their effective cam surfaces extend at about the same angle (45) to the direction of extension of the needles. It will also be observed, by reference to Fig. 9, that about the time that the hook of a needle, during the downward movement imposed by its actuating cam, engages and starts to pull down yarn, the yarn engaging element of an adjacent sinker, under the impulse of its actuating cam, starts to rise and pull up yarn. The distance to which the yarn-engaging elements of the sinkers rise is about equal to the distance to which the needles are depressed during the yarn pulling movement. Thus,

loops are formed in about half the time required with stationary sinkers.

It will also be seen, by reference to Fig. 9, that when a needle has reached its maximum depression, it has necessarily drawn yarn from the source of supply and has also drawn on yarn that "has been engaged by the preceding needles. The yarn therefore extends in a zi zag course along an arc of the needle cylin tance from one needle to between the second and third needles beyond such needle, the yarn thus engaging angular-l about three needles and three smkers an however, the sinkers should remain on or about one level and if the needles were relied upon, wholly or mainly,to pull the yarn, the time required to form a loop would be approximately twice as great, the zigzag course of the yarn would extend along a much longer are, and in its zigzag course the yarn would change its direction of extension a substantially greater number of times.

It will also be observed that the effective cam surface of the sinker actuating cam f, as well as the efiective cam surface of the needle actuating cam, is substantially straight. Thereb the yarn is pulled at a substantially uni orm rate from the beginer measured by the dischanging its direction of extension about six times. If,

ning to the end of the loop-forming movement.

It is clear that the strain imposedon the yarn rapidly increases with the number of changes of direction that it is forced to take while it is being acted upon by the needles and sinkers, and that by the described simultaneous reverse movements of needles and sinkers, the strain on the yarn is reduced to a minimum with little danger of yarn breakage. I

In the diagram of Fig. 9, and in the above descriptiom l have assumed that, in my invention, as long stitches are drawn as in the method of knitting, with which a comparison is instituted, I have hereinbefore explained why, in my invention, a shorter loop may be drawn than in the case of ordinary knitting and yet produce the same sized loop in the finished fabric. If this were illustrated in the diagram, it would show a zig zag course of the yarn not only of shorter length, but with convolutions of smaller depth, than are actually shown.

It should be' understood that I make no claim broadly to a sinker which is tiltable on a transverse axis, or even to a sinker which is made tiltable b bevelling the lower edge thereof from a me iate point upwardly toward the rear; nor is it novel to actuate such a sinker by a cam operating on the heel thereof. Such a sinker is disclosed in the prior art. It has been proposed to employ such a sinker as a special slnker in connection with regular sinkers to produce long loopsalong a given Wale for the purpose of formin a mock ribor lineof open work in a stocking; but not only is the patented contrivance believed to be impracticable for the specified purpose, but it is wholly inoperative, and is not intended to be operative, to attain the main object of my invention. Indeed, the evils which I more particularly seek to remedy would be exaggerated by a mere lifting of one particular sinker; because the only result of such operation would be to increase the vertical dimensions of the zigzag extension of the yarn at the stitchforminglocus when such sinker is operating, without diminishing the number of convolutions (up and down extensions) of the yarn forming the zigzag. In other words, to attain the rincipal object of my invention, mere lifting of isolated sinker would be ineffective; it being essential that the lifting movement shouldbe ap lied to all the sinkers or at least to a'consi erable number of successive sinkers and the lift of each sinker should take place about simultaneously with the downward movement of an adjacent needle immediately following the engagement of its hook with yarn from the source of supply. By utilizing the sinkers to effect a considerable lift of the yarn at this time, the movement of depression of the 4 to 8 inclusive.

needle, after its hook engages the yarn, may be-correspondingly shortened. This cooperative action between the needles and the sinkers permits of a reduction in the extreme up and down dimensions of the zigzag path of the yarn, and greatly reduces the number of its convolutions, thereby materially re ducing the strain on the yarn, as hereinbefore fully explained.

However, as explained in the introductory part of the specification, it is possible, without changing the described mode of operation of the sinkers, and while still continuing to attain the main object of my invention, to vary the degree of lift of the sinkers in order to produce a loose welt, or vary the diameter of the leg portion, or facilitate the introduction of an extra thread into the heel, toe and sole of the foot.

I accomplish the purpose of making a loose stitch throughout any desired circular part of the web of the stocking by making the cam f vertically adjustable as in Figs. In these figures, the cam f is held in the position shown in Fig. 4: (which corresponds to the position shown in Figs. 13) by securing it to a lever z' mounted on a bracket j secured to the machine frame. Lever i is pressed by a spring 1 against a cam la, which is maintained in fixed position during the regular knitting. Cam k is mounted on a bell crank lever m pivoted on the machine frame. Lever on has secured to its other end a plurality of adjustable pins n, which are adapted to be engaged, at different stages of the knitting operation, by any suitable pattern mechanism, as, for example, by cams 0 on a pattern disc 77 of the character of that set forth in the H. E. Houseman Patent No. 1,359,249, dated November 16, 1920. When a cam on the pattern disc 2 engages one of the pins 11 the lever m is swung on its pivot so as to project the cam is inward, thereby depressmg cam 7. Hence the yarn-engaging ends of the sinkers are successively raised above the maximum height to which they are raised when sinker f is in its lower, or what may be called its normal, position, and

therefore longer than normal loops are formed.

The extent to which the yarn-engaging ends of the sinkers are lifted is obviously a matter of adjustment of the pins n. Therefore the length of the loops may be governed to a nicety.

Therefore, by means of a single adjust- I able cam f, ,the strain on the yarn may be greatly reduced, and any de cc of looseness of stitch may be secure whether in the welt, or in any part of the leg. 'H0wever, in double sole knittin where, in order to accommodate an additional yarn, it is necessary to draw relatively long loops in the sole while continuing to draw normal normal degree.

loops in the upper part of the foot, it is ob vious that approximately only one half of the sinkers (those in the rear needle-bank) should be tilted beyond the normal osition, while the others should be tilted on y to the To effect this result, the sinkers in the rear needle bank are rovided with special heels 1" (see Fig. 4) which, in the rotat on of the needle cylinder, are normally successively engaged by a cam 7' similar to cam f. This cam f may be normally raised so high as to be inoperative; or it may be normally so positioned that it actuates the rear half of the sinkers in precisely the same manner and to precisely the same degree that they are actuated by cam f; or cam ff may alone be relied on to normally actuate the rear half of the sinkers.

In any case, however, the cam f is adapted I to be depressed to such a distance that it will operate to tilt the rear sinkers that these alone will produce longer loops, cam f continuing to function to tilt only the front sinkers to produce loops of normal length. Cam f is carried on-the end of a sprlngpressed lever i',which is engaged by a cam k mounted on one end of a bell crank lever m. This lever may be actuated in the same way as lever m is actuated: namely, by cams on the pattern disc [7.

hen the machine is about to start on the body of the foot of the stocking (namely, that part of the stocking between the heel lever m on its-axis, pushin in cam k. which depresses cam f, there y impartingthat greater degree of tilt to the rear sinkers needed to secure the-desired loose stitches and toe), a cam on the cam disc p swings movement. As is also well understood, and

as will' be clear by reference to Fi 9, the pointin the arc of oscillation at w ich the stitch is formed in the reverse stroke of the.

needle cylinder is difl'erent from that at which the stitch is formed in the advance stroke of the cylinder, only the latter point corresponding to the-stitch-forming point in circular knitting. It is therefore necessary to provide a special cam 7" (see Fig. 7) at this different point in the arc of oscillation, so that the sinkers may be tilted at'the knitting ints in both directions of travel of the need e cylinder. This cam may be fixedly supported in thesame way inwhich cam f is shown as supported in Figs. 1-3; or in case it is desired to loosen the stitch'during the knitting of the'heel and toe, it ma be shifted simultaneously with cam fund by be identical with that described for sin ing wherein cam f is secured to a lever i w ich (like lever i) is mounted on the bracket j and .is pressed by a spring Z against a cam is, which (like cam is mounted on the bell crank lever m. When lever m is swung on its pivot'so as to project cam 7: inward and depress cam f, it at the-same time projects cam is inward and depresses cam f Cam F Will, of course, operate the sinkers during circular knitting'and during the forward stroke of the needle cylinder in reciprocatory knitting, just as cam f will operate the sinkers in the reverse travel of the needle cylinder during reciprocatory knit ting; but in each case sucho eration of the sinkers will be at a point relatively remote from the point of knitting and will be inoperative to produce any effect in the knitting operation.

Having now fully-described my invention, what I claim and desire to protect by Letters Patent is: V

1. In a circular knitting machine, the

combination with a needle cylinder and its needles and sinkers, of means to move the needles successively down to cause their hooks to engageand pull down yarn and substantially simultaneously with such yarnpulling downward movement lift the respectively adjacent yarn-engaging elements of the sinkers a distance substantially equal to the distance to which the needles are depressed duringsuch yarn-pulling movement, thus, by the simultaneous movement of the needles and sinkers substantially the same distance in" opposite directions, forming loops in about half the time required with stationary sinkers, with reduction in strain on the yarn and in the maximum length of loop required to be drawn.

2. In a circular knitting machine, the combination with a needle cylinder and its needles and sinkers, of a cam adapted to move the needles successively down to cause their hooks to engage and pull down yarn, and a cam adapted, substantially simultaneously with such yarn-pulling downward movement, to lift the respectively adjacent yarn-engaging elements of the sinkers and thereby pull up yarn, the efi'ective cam surfaces of the two cams during such yarn pulling movements extending at substantially the same angles to the direction of extension of the needles so as to divide the loop-forming operation substantially equally between the first cam and the needles and the second cam and'the sinkers.

3-. In a circular knitting machine, the combination with a needle cylinder and its needles and sinkers, of a cam adapted to move the needles successively down to cause their hooks to engage and pull down yarn, and a 'cam adapted, substantially simultaneously with such yarn-pulling downward movement, to lift the respectively adjacent yarn -ngaging elements of the sinkers and thereby pull up yarn, the eifective cam surfaces of each cam during such yarn-pulling movements extending at substantially fortyfive degrees to the direction of extension of the needles and about ninety degrees to each other.

4. In a circular knitting machine, thecombination with a needle cylinder and its needles and sinkers, of a cam adapted to move the needles successively down to cause their hooks to engage and pull down yarn, and a cam adapted, substantially simultaneousy with such yarn-pulling downward movement, to lift the respectively adjacent yarn-engaging elements of the sinkers and, thereby pull up yarn, the effective cam surfaces of both cams during such yarnulling movement being substantially straig t and extending at substantially equal angles to the direction of extension of the needles, whereby during the loop-forming operation the yarn is pulled substantially equally in opposite directions and at a substantially uniform rate from the beginning to the end of the loop-forming movement.

,5. In a circular knitting machine, the combination with a needle cylinder and its needles and sinkers, of a cam adapted to move the needles successively down to cause their hooks to engage and pull down yarn,

and a cam adapted, substantially simultaneously with such yarn-pulling downward movement, to lift the respectively'adjacent yarn-engaging elements of the sinkers and thereby pull up yarn, thereby dividing the loop-forming operation between the first cam and the needles and the second cam and the needles, and means to adjust the second cam to cause it to vary the amount of yarn which it pulls in the loopforming operation and thereby vary the lengths of the loops formed by the coaction of the two cams with the needles.

6. In a circular knitting machine, the com- I bination with a needle cylinder. its needles. and cams adapted to successively lower and raise the needles in the'stitch-forming operation, of a cam acting to raise the yarn-en-f gaging elements of all the sinkers simul- 'taneously with the latter part of the downward movement of respectively adjacent needles, and another cam which is adjustable to raise only the yarn-engaging elements of the sinkers of the rear bank simultaneously with the latter part of the downward movement of the respectively adjacent needles to a level higher than that to which the yarnengaging elements of the sinkers of the front bank are raised in the knitting of the same courses.

7. In a circular knitting machine, the 'combination with a rotatable needle cylinder and needles and sinkers arranged in alternate relation circumferentially thereof, of cams adapted to successively act upon the rotating needles and lower and raise themin the stitch-forming operation, whereby at any given time the yarn, at the locus of stitch formation, extends in a zigzag course under successive needle hooks and over successive sinkers, a second cam adapted to successively act upon certain of the sinkers to effect a raising and lowering of the yarnengaging elements thereof in the stitchforming operation, and a third cam adapted to successively act upon other sinkers to elfect a raising and lowering of the yarn-engaging elements thereof in the stitch-forming operation to a higher level than that to which the yarn-engaging elements of the 1 first sinkers are raised, thereby drawing loops of, different sizes on different needles by the cooperative action of the needles and the two cams.

In testimony of which invention, I have 90 hereunto set my hand, at Philadelphia, Penna, on this 5th day of June, 1924.

HAROLD E. HOUSEMAN. 

